Vehicle having a brake device

Abstract

A vehicle has a brake device with a friction brake unit, an electrical brake unit and a brake control device. In order to provide a vehicle having a reliable and structurally simple brake device, the friction brake unit has brake components made of a composite material and the brake control device includes a monitoring device for monitoring a brake operation performed by the electrical brake unit.

Claims

1. A vehicle, comprising: a braking device having a friction brake unit, an electrical brake unit and a brake control device; said friction brake unit including brake components made of a composite material; and said brake control device having a monitoring device configured for monitoring a braking operation performed by said electrical brake unit; said brake control device being configured, in a normal mode of operation, to effect braking primarily by way of the electrical brake unit; said brake control device being configured, in a case in which said monitoring device detects a limitation of said electrical brake unit, to trigger a safety mode and to effect braking primarily by way of said friction brake unit; and wherein said brake components of said friction brake unit are configured not to exceed an oxidation limit temperature of said composite material in the normal mode of operation and to enable operation in the safety mode within a temperature range above the oxidation limit temperature.

2. The vehicle according to claim 1, which comprises a drive device, and wherein said electrical brake unit includes at least one drive unit of said drive device.

3. The vehicle according to claim 2, wherein at least one of said brake components of said friction brake unit and a drive unit of said drive device are associated with a respective one of a plurality of vehicle wheels, and wherein said drive unit is a component of said electrical brake unit.

4. The vehicle according to claim 1, wherein said brake control device has at least two brake control units for controlling said electrical brake unit, and wherein said at least two brake control units are redundant to each other or diversely redundant in design.

5. The vehicle according to claim 1, wherein said brake control device has at least two brake control units for controlling said electrical brake unit and said monitoring device comprises at least two monitoring units, which are different from each other and are each associated with a different brake control unit.

6. The vehicle according to claim 1, wherein said brake control device is configured to control said friction brake unit for a braking effect compensation in a case in which said monitoring device detects that a braking effect of said electrical brake unit is insufficient with respect to a desired braking effect.

7. The vehicle according to claim 1, wherein said composite material is a fiber composite material.

8. The vehicle according to claim 7, wherein said composite material is a carbon fiber composite material.

9. The vehicle according to claim 1, wherein said composite material is a ceramic composite material.

10. The vehicle according to claim 1, wherein said composite material has an oxidation limit temperature in a range from 300 to 500 C.

11. The vehicle according to claim 1, wherein said composite material is configured for damage-free operation up to temperatures in a range from 800 to 1,400 C.

12. The vehicle according to claim 1 configured as a motor vehicle.

13. The vehicle according to claim 1 configured as a rail vehicle.

14. The vehicle according to claim 13, being a multiple unit for high-speed traffic with a maximum operating speed of at least 350 km/h.

15. A method of operating a braking device of a vehicle, the braking device having a friction brake unit with brake components made of a composite material, an electrical brake unit and a brake control device, the method comprising: in a normal braking mode, primarily braking the vehicle with the electrical brake unit; monitoring a braking operation performed by the electrical brake unit with a monitoring device; if the monitoring unit detects a limitation of the electrical brake unit, activating a safety braking mode for primarily braking the vehicle with the friction brake unit; in the normal braking mode, selectively assisting a braking operation of the electrical brake unit with the friction brake unit and thereby operating the friction brake unit at temperatures below an oxidation limit temperature of the composite material of the brake components; and in the safety braking mode, primarily braking the vehicle with the friction brake unit and, on occasion, operating the friction brake unit at operating temperatures above the oxidation limit temperature of the composite material.

16. The method according to claim 15, wherein the normal mode encompasses a service braking operation and the safety mode encompasses an emergency braking operation.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) Exemplary embodiments of the invention will be described in more detail with reference to the drawings, in which:

(2) FIG. 1 shows a rail vehicle in a schematic side view, with a drive device and a braking device,

(3) FIG. 2 shows a drive unit of the drive device,

(4) FIG. 3 shows a circuit of the braking device with a brake control device,

(5) FIG. 4 shows an alternative brake control device with redundant brake control units,

(6) FIG. 5 shows a drive axle of the rail vehicle with a motor and a brake disk in a plan view and

(7) FIG. 6 shows a chassis of a motor vehicle in a plan view.

DESCRIPTION OF THE INVENTION

(8) FIG. 1 shows a rail vehicle 10 designed as a multiple unit in a highly diagrammatic side view. It has running axles 12 and drive wheel units designed as drive axles 14, which are driven in a traction mode by a drive device 15. The drive axles 14 are mounted in motor bogie devices, in particular power trucks. The rail vehicle 10 is designed for high-speed transport and has a maximum permitted speed in passenger service of 350 km/h.

(9) In the embodiment shown as a multiple unit, the rail vehicle 10 corresponds to a group of cars, which are each designed for transporting passengers, with at least one of the cars being designed as a rail car with drive axles 14. In an alternative embodiment, the rail vehicle can be designed as a group comprising a traction vehicle and a set of driveless passenger carriages coupled thereto.

(10) The drive device 15 has a set of drive units 16, which are each associated with a different traction bogie device. The drive units 16 have, as shown in FIG. 2, drive motors 18, which are designed in particular as a three-phase machine and are respectively provided for driving a different drive axle 14. In order to supply the drive motors 18 with electrical power, the drive units 16 also each comprise at least one power supply unit 20 that is operatively connected thereto. This is known from the prior art and has an inverter (not shown), which in a traction mode of the drive unit 16, as a result of the actuation of electronic switching elementsalso called valvesof an electronic power device, starting from a direct voltage, generates a current variable in voltage and frequency according to the power to be provided for the associated drive motor(s) 18. The energy available for this purpose in an associated direct voltage intermediate circuit is obtained from a high voltage power supply 25. Energy obtained therefrom is led in a traction mode via a current collector, and further electrical conversion devices (not shown), such as in particular a transformer or a voltage transformer, a rectifier, etc. to the drive device 15. In the traction mode of the drive units 16, the switching elements of the inverters are controlled in accordance with a switching strategy to generate a drive torque to the associated drive axles 14 via the drive motors 18.

(11) The rail vehicle 10 also has a braking device 21. This comprises a friction brake unit described in more detail below 22 and an electrical brake unit 24. In a normal braking mode of the braking device 21, a braking operation of the rail vehicle 10 occurs at least by the drive units 16, which in each case have the function of an electrodynamic brake. Therefore, the drive units 16 each form a part of the electrical brake unit 24.

(12) For controlling the friction brake unit 22 and the electrical brake unit 24, the braking device 21 has a brake control device 26. This is illustrated in detail with reference to FIG. 3. In the figure, only one of the drive units 16 is shown, wherein the following description can be applied to the other drive units 16 that are not shown.

(13) The brake control device 26 comprises a brake control unit 28, which in an active state is provided to control the power supply unit 20 of the drive unit 16 for a braking operation of the electrical brake unit 24. For this braking operation, the brake control unit 28 is provided to control the switching elements of the inverter of the power supply unit 20 according to a switching strategy in such a way that a braking torque is generated on the associated drive shaft 14 via an associated drive motor 18. With a braking operation by the electrical brake unit 24, the drive motor 18 acts as a generator, with the energy converted into electrical power during the braking operation being converted by a braking resistor 32 into heat. Alternatively or additionally, the energy can be fed back into the high voltage power supply 25, be used on the vehicle or be stored in a mobile storage facility.

(14) The brake control unit 28 is operatively connected to the power supply unit 20. In addition to an interface for the power supply unit 20, the brake control unit 28 has a further interface through which it is operatively connected to a sensor unit 34. The sensor unit 34 serves to detect a vehicle speed characteristic v and a mass characteristic m, representing input parameters for the generation of control signals 44 by the brake control unit 28.

(15) The brake control device 26 also comprises a brake control unit 30 which is designed to control components of the friction brake unit 22. In particular, during actuation of the friction brake unit 22 it controlsvia a rail vehicle main air line 38actuators, by which a contact between brake components 31 designed as a brake disk (see also FIG. 5) and brake linings is produced.

(16) The brake control device 26, in particular its brake control units 28 and 30, is also operatively connected via interfaces to the rail vehicle control technology, by being connected to a data bus 36 of the rail vehicle 10. Further input parameters for the brake control units 28, 30 can be provided by way of these further interfaces, such as in particular a characteristic that represents a braking effect required by the driver, by an automatic vehicle controller and/or an emergency brake. The brake control device 26 is supplied with electrical energy by an on-board power supply 40.

(17) On the basis of the above input parameters, in a normal braking mode, in which it is in an active state, the brake control unit 28 generates control signals 44, which control the power supply unit 20 in accordance with a particular braking effect to be achieved. For this purpose, the brake control unit 28 has at least one arithmetic unit 46 and a storage unit 48 in which software is stored. Especially the braking mode switching strategy for the switching elements of the inverter is programmed in this software. In a normal braking mode of the braking device 21, the electrical brake unit 24 has a higher priority than the friction brake unit 22, wherein the largest possible part of the braking effect to be achieved is to be generated by the electrical brake unit 24 and the friction brake unit 22 when neededin particular in a low speed rangeserves to support the electrical brake unit 24.

(18) A monitoring device 50 of the braking device 21 is associated with the brake control unit 28 and is provided to monitor the braking effect achieved, or which is achievable, by the electrical brake unit 24. For this purpose, a braking effect characteristic, in particular a braking torque characteristic is used and compared with a desired value. The braking effect characteristic can for example be detected by an acceleration sensor and/or is determined by an evaluation of the speed characteristic v. Alternatively or additionally, the braking effect characteristic can be determined by monitoring the control signals 44 generated by the brake control unit 28. In addition, as shown in the figure, an electrical quantityfor example, an electrical currentof the associated drive motor 18 and/or the power supply unit 20 can be monitored, in particular, be evaluated.

(19) In the normal braking mode of the braking device 21for example during normal service brakinga desired braking torque is predominantly provided, in particular as far as possible by the electrical brake unit 24. In this normal braking mode, the brake control unit 30, which is operatively connected to the rail vehicle main air line 38, controls the friction brake unit 22, whose function, as described above, includes supporting the electrical brake unit 24in particular in a low speed range.

(20) If it is detected by the monitoring device 50 that the braking effect generated, or achievable, by the electrical brake unit 24 is not sufficient to provide a desired brake torque, the electrical brake unit 24 is deemed defective and the brake control device 26 activates a safety mode of the friction brake unit 22 in which it compensates for the lack of braking torque, if necessary, generates the total desired braking torque.

(21) The limitation of the electrical brake unit 24 can be due to a fault in a drive unit 16 and/or a brake control unit 28 associated therewith.

(22) FIG. 4 shows a specific embodiment of the brake control device 26. In this example, it has two brake control units 28a, 28b, which are each provided, as described above, for controlling an identical power supply unit 20 of the drive device 15 for a braking operation of the electrical brake unit 24. The monitoring device 50 has two monitoring units 50a and 50b, which are each provided to monitor a different brake control unit 28a or 28b.

(23) The brake control units 28a, 28b are each connected by a switching unit 52 to the power supply unit 20. This switching unit 52 schematically illustrated in the figure can have a mechanical switch or be implemented as a software solution.

(24) In the normal braking mode, the electrical brake unit 24 is basically controlled by the brake control unit 28a. The brake control unit 28b is in an inactive state due to a corresponding position of the switching unit 52. A braking operation of the electrical brake unit 24 is monitored, as described above, by the monitoring unit 50a. If, as described above, it is found that a desired braking torque intended for the electrical brake unit 24 cannot be provided thereby, the switch unit 52 is actuated by the monitoring unit 50a, so the brake control unit 28a is put in an inactive state and the brake control unit 28b is activated. The electrical brake unit 24 then continues to be controlled by the brake control unit 28b.

(25) A second monitoring unit 50b, different from the first monitoring unit 50a in terms of software and/or hardware, is associated with the brake control unit 28b. This is provided to monitor the braking effect achieved, or which is achievable, by the electrical brake unit 24 with the brake control unit 28b. For this purposeas already described abovea braking effect characteristic, in particular a brake torque characteristic, is detected or determined, and compared with a desired value.

(26) If it is detected by the second monitoring unit 50b that the braking effect generated, or which is achievable, by the electrical brake unit 24 is not sufficient, the brake control unit 28b is deemed defective and the safety mode of the friction brake unit 22 is activated as described above.

(27) The brake control units 28a, 28b are designed to be diversely redundant to each other. They are based on differing technologies. A technology encompasses the structuralor hardware-relatedand/or algorithmicor software-relateddesign. In an exemplary configuration, the first brake control unit 28 can be in the form of a signal processor, with the algorithmic implementation corresponding to a field-oriented control. The brake control unit 28b can be designed as a field-programmable gate array (FPGA) or as an in the field programmable gate array, with the algorithmic implementation corresponding to a switching-oriented control.

(28) FIG. 5 shows a drive axle 14, its associated drive motor 18 and a brake component 31 of the frictional braking unit 22. This is designed as a brake disk, which is made of a composite material. In particular, the brake component 31 is designed as a ceramic brake disk made of a C/C-SiC carbon fiber composite material. In the above-described normal braking mode of the braking device 21, the friction brake unit 22 is relieved by the electrical brake unit 24 until it does not exceed the corresponding oxidation temperature limitin the range of about 300 C. to 500 C. for the material selected. If the safety mode of the friction brake unit 22 is activated, the braking components 31 can handle the corresponding overload very well since they are designed for damage-free operation up to temperatures of over 800 C., preferably up to 1,300 C., in other words, are overload resistant.

(29) The considered embodiment of a rail vehicle is exemplary. In alternative embodiments, vehicles are conceivable which are not mounted on rails, such as, for example, a car, a bus or a truck.

(30) FIG. 6 shows in a highly schematic plan view a chassis 54 of a motor vehicle 56. This is designed in particular as a passenger vehicle (car), with a design as a truck or bus also being conceivable. An outer contour 58 of the motor vehicle 56 is shown in broken lines and schematically.

(31) The chassis 54 has a set of driving wheel units, which are each designed as drivable vehicle wheels 60. The vehicle wheels 60 are mechanically independent of one another and form, in particular, autonomous drivable units. A drive unit 16 of the drive device 15 of the motor vehicle 56 is in each case associated with the vehicle wheels 60. The drive units 16 each have a drive motor 18 designed as a wheel hub drive. Reference is made to the above description of the drive units 16, which can be applied mutatis mutandis to the drive units 16, in relation to the design and operation of the drive units 16. The drive units 16 also form components of an electrical brake unit 24.

(32) At least one braking component 31 of a friction brake unit 22 respectively is also associated with the vehicle wheels 60. The braking components 31 are designed as brake discs, which are made of a composite material.

(33) The electrical brake unit 24 and the friction brake unit 22 are components of a braking device 21 of the motor vehicle 56, further having for control thereof a brake control device 26 comprising a monitoring device 50. The above description of the braking device 21, in particular in relation to its electrical brake unit 24, friction brake unit 22 and brake control device 26 with the monitoring device 50 can be applied mutatis mutandis to the corresponding units in the present exemplary embodiment, with unnecessary repetition being omitted.

(34) The exemplary embodiment of FIG. 6 can also be applied in rail vehicles, for example in trams.