Patent Application
20240157984
The invention relates to a ground contact and to a method for operating a rail vehicle, the rail vehicle having a ground contact on a wheel set having an axle and wheels, the ground contact having a housing unit, a contact device and a sensing device, the contact device having a contact piece which is disposed on a contact surface of an axle, an electrical sliding contact being formed between the contact surface and the contact piece.
Ground contacts and methods of this kind are well known from the state of the art and are commonly used on axles of rail vehicles, in particular electrically driven rail vehicles. Ground contacts serve to transmit electrical currents via an axle of a wheel set to a rail. The known ground contacts can be disposed on an axial side of an axle and can be non-rotatably connected to an axle support of the rail vehicle or be connected to the axle support for co-rotation relative to the axial side. The ground contact comprises a housing having a flange-like housing lid or a housing cover which is disposed on an axial side, contact pieces made of graphite being electrically connected to the axle or corresponding slip rings or slip disks within the housing for transmitting a current. Furthermore, disposing a sensing device or a flange-like sensor housing on the housing cover is known. The housing cover has an opening through which, for example, a rotary encoder of the sensing device can detect signals generated by axial rotation. These signals are transmitted via a cable to a vehicle control system which generates an axle speed, impulses for an engine control or a brake system therefrom. Thus, the sensor transmits a signal to a vehicle control system, which processes the signal for controlling purposes. A ground contact of this kind is known from EP 2 423 068 A1, for instance.
Because the contact pieces of the ground contacts are in constant contact with the axle or rotating components of the axle, they are worn because the material or graphite of the contact pieces is abraded. Thus, it is necessary to frequently conduct maintenance on ground contacts in order to ensure that respective ground contact functions. This maintenance is always carried out in a depot for rail vehicles in the course of a maintenance interval, whereby a partial disassembly of the housing unit for examining the contact pieces is required. This is also when contact pieces are replaced which are not fully worn yet. In total, this results in an increased effort for carrying out maintenance on the ground contacts and for replacing the contact pieces.
Therefore, the object of the invention is to propose a method for operating a rail vehicle and to propose a ground contact and a monitoring system having a ground contact which allows an improved operation.
This object is attained by a method having the features of claim 1, by a ground contact having the features of claim 15 and by a monitoring system having the features of claim 16.
In the method according to the invention for operating of a rail vehicle, the rail vehicle is formed having at least one ground contact on a wheel set having an axle and wheels, the ground contact having a housing unit, a contact device and a sensing device, the contact device having a contact piece which is disposed on a contact surface of an axle, an electrical sliding contact being formed between the contact surface and the contact piece, the ground contact comprising a measuring unit having a measuring device, at least one sensor of a sensing device of the measuring device being disposed on the contact device and/or adjacent to the contact device, a measured value of the contact device being determined by means of the sensing device, the measured value being processed by means of a processing unit of the measuring device and a parameter describing an operating state of the wheel set and/or a guide rail being determined.
The ground contact is disposed on the wheel set, which can be a trailing wheel set, a driving wheel set or an individual wheel set having one or a plurality of axles. The axle or axles of the wheel set each have two wheels, which are seated on a guide rail of the rail vehicle or on one rail each and which can roll thereon. The ground contact disposed on the axle and, within the housing unit, has the contact device having at least one contact piece. The contact device serves to mount and establish an electrical connection with the contact piece. The axle or a component disposed on the axle forms the contact surface of the axle which is rotatable relative to the contact piece. By means of the contact piece, the axle can be contacted radially or axially. Furthermore, the contact device can comprise a plurality of contact pieces. In particular, the contact piece can be made of graphite.
The method according to the invention intends that the ground contact comprises a measuring unit having a measuring device, said measuring device having a sensing device having at least one sensor. The sensor is disposed on the contact device and/or adjacent to the contact device or arranged as close as possible to the contact device or the contact piece. A measured value of the contact device or the contact piece is registered by means of the sensing device or the sensor. This measured value is a physical measured variable which is directly operably linked to the contact device and which is variable during an operation of the ground contact. Then, the measured value or measured variable measured by the sensor is processed by means of the processing unit and a parameter is determined which is suitable for describing an operating state of the ground contact and/or the guide rail. The parameter can be a parametric value, a characteristic variable, a key figure or a data set. The parameter can also be included in a data set. In particular, it is intended to digitally process the measured values by means of the processing unit in order to obtain a parameter that is suitable for further digital processing. Thus, the processing unit is formed by at least one digital electronic circuit which can process analogue and/or digital signals of the sensor. The processing unit can also be a programmable logic controller (PLC), an integrated circuit (IC) or a computer, for example.
As a result of the processing unit determining the parameter suitable for describing the operating state of the ground contact, it becomes possible to determine the operating state of the ground contact, the wheel set and/or the guide rail or to monitor the ground contact. Since the operating state of the ground contact also largely depends on the state or operating state of the wheel set and/or the guide rail, the parameter can also describe the operating state of the wheel set and the guide rail. For example, the operating state can be a state of wear, so that it becomes possible to make a statement about the state of wear based on the parameter. Overall, maintenance on the ground contact, the wheel set and the guide rail can be carried out in a more targeted manner without having to adhere to regular maintenance intervals. Overall, it thus becomes possible to operate a ground contact, a wheel set or a guide rail, and thus a rail vehicle, more cost-effectively in total.
As a measured value, a speed of the axle, an acceleration, a frequency, a temperature, an air humidity, a force, a current, a voltage, a distance, a mass and/or a location can thus be registered and processed continuously or discontinuously. Based on the speed of the axle, a driving speed or a driving route of the rail vehicle can be measured. For example a rotary encoder on the axle or another suitable sensor can be used for this. A temperature can be measured on the ground contact or directly on the housing unit or the contact device using a temperature sensor, so that a possible warming of the wheel so that a possible overheating of a bearing of the axle can be determined. A force can be determined by means of a strain gauge, a force sensor, a pressure sensor or the like. For example, a contact pressing force of the contact piece can thus be measured. A current or a voltage can be measured using an ammeter or a voltmeter as a sensor. For example, a current discharged via the ground contact can then be determined. A location of the ground contact can be easily determined using a satellite navigation system, such as GPS. The measured value or the measured values can be determined or processed continuously or consecutively. It is also possible to register and process the measured value or measured values discontinuously, for example at set points in time or on certain occasions.
It is especially advantageous if at least one acceleration sensor, which can be disposed on the contact device, preferably on the contact piece, is used as a sensor. The acceleration sensor or vibration sensor can be used for measuring an eigenfrequency and/or resonant frequency of the contact piece or the entire ground contact. For example, by means of the acceleration sensor, a movement of the contact piece on the axle can be detected, in which case conclusions regarding a design of the guide rail or a wheel flat on a wheel rim of the wheel can be drawn from the movement. Thus, an irregularity in the course of the guide rail can be easily determined. Special measurement drives or on-site inspections of the guide rail for determining such defects are thus no longer necessary. Furthermore, a contact piece change as a result of wear or abrasion on the axle causes the eigenfrequency and/or resonant frequency of the contact piece to change. The difference between a new and a worn contact piece can result from this. Since the contact piece is regularly in contact with the axle during the drive of the rail vehicle, the processing unit can derive a change of the contact piece from an eigenfrequency and/or resonant frequency change of the contact piece. For example, the eigenfrequencies and/or resonant frequencies of new and worn contact pieces can be stored in the processing unit, in which case the processing unit can make a comparison and determine a state of wear or the use of the contact piece without further calculations. This wear can then be output in the form of the parameter. Furthermore, damage to the contact piece can easily be determined.
The processing unit can register and store the measured values of sensors and/or the parameters at regular time intervals, when a change occurs, or continuously. Accordingly, it can be envisaged that the measured values and/or the parameters are only registered and stored when the values change in order to minimize the amount of data. Alternatively, a continuous, in other words, a consecutive registration and storage can be intended. By storing the measured values and/or parameters, the processing can be carried out even after the registration. For example, measured values can be registered during a drive of the rail vehicle, in which case the determination of the parameter or the parameters can then be carried out once the rail vehicle is being inspected in a depot. In this manner, the condition of a guide rail along a route of the rail vehicle can be determined after a drive, for example.
The measuring device can transmit the measured values and/or parameters to an evaluation unit, the measured values and/or parameters being storable in a database of the evaluation unit and/or being processable by means of an evaluation device of the evaluation unit. The evaluation unit can thus comprise the database and the evaluation device. Thus, the evaluation unit can serve to collect and process the measured values and/or parameters and can be a computer. For example, the evaluation device can display or output a result of an evaluation to an operator. The evaluation unit can have a larger range of functions than the processing unit. In principle, however, it is also possible to integrate the processing unit in the evaluation unit and vice versa. In principle, an evaluation unit of this kind can also be provided as a module of the rail vehicle irrespective of the ground contact.
The measured values and/or parameters of the measuring device are transmittable to the evaluation unit via a data link by means of a transmitting unit of the measuring device, the evaluation unit being configured to be disposed at a distance to the measuring unit or integrated in the measuring unit. If the control device or the evaluation unit is integrated in the measuring unit, the data link can be formed easily by a line connection. It is then also possible to install parts of the measuring device, such as the processing unit and the control device and also the evaluation unit, elsewhere on the rail vehicle, for example on an operator's stand. When the measured values and/or parameters are transmitted, data can be exchanged on the basis of a transmission protocol, for example. The data link can be established continuously, at regular intervals or so as to be triggered by incidents. Overall, this allows to collect and evaluate the data collected by the measuring device. An analysis of certain conditions and incidents then provides various opportunities for evaluation, by means of which the operation of the ground contact, the wheel set and the guide rail or the rail vehicle can be optimized.
The data link can be formed via an external data network. In this case, the data link can be formed via a mobile network, a wireless network, a satellite connection, the internet or any other radio standard on its own or in combination. If the evaluation unit is disposed at a distance to the measuring unit, it can also be disposed outside of the rail vehicle, far away from the rail vehicle and so as to be stationary, for example in a building. In particular, it thus becomes possible to monitor a function of the ground contact and the wheel set on the rail vehicle without a person having to perform this task on the rail vehicle itself.
A data link to the evaluation unit and/or to the measuring unit can be formed by means of a user unit, the measured values and/or parameters being transmittable and configured to be output to the user unit. The user unit can be a computer which is independent of the evaluation unit and/or the measuring unit. This computer can be a stationary computer, a mobile device, or the like, by means of which another data link for exchanging data with the evaluation unit and/or the measuring unit can be established. For example, the data can be exchanged via an external data network, such as the internet. In this manner, data processed by the evaluation unit or measured values and/or parameters processed using the evaluation device can be provided to a wider range of users. For example, the evaluation unit can be a server with a software which transmits the information stored in the database of the evaluation unit to the user unit. This transmission can take place since a website with selected information, such as a current state of wear of the contact piece is provided.
The processing unit or the evaluation unit can evaluate a time curve of the measured values and/or parameters and determine a state of wear of the contact piece, the wheel set and/or the guide rail, taking into account a time-dependent component and/or a component depending on measured variables relevant for the wear. Thus, not only can information be provided regarding the current state of wear, it can even be determined at which point in time a contact piece or wheel, for example, will approximately have become worn. Thus, a maintenance interval for the ground contact or other components of the wheel set can be scheduled precisely and the timing can be optimized. Furthermore, the point in time at which certain incidents took place can be determined by means of the time curve. On this basis, a scheme can be derived if incidents occur repeatedly. For example, a guide rail in poor condition or an increased wear can be observed when driving on a certain section of the route.
A vibration of the contact piece can be registered by means of the sensing device, the processing unit being configured to determine an eigenfrequency and/or a resonant frequency of the contact piece and/or the axle, the processing unit or the evaluation unit being configured to determine a state of wear of the contact piece, the wheel set and/or the guide rail. The shape, in particular the height of the contact piece can change when the contact piece is worn, in which case the shape change can change the eigenfrequency and/or the resonant frequency of the contact piece. A state of wear of the contact piece and/or the axle can be determined from the eigenfrequency and/or the resonant frequency by means of the processing unit. If the eigenfrequency and/or the resonant frequency changes as carbon is increasingly abraded from the contact piece or from a component of the axle, conclusions regarding the state of wear of the contact piece and/or the axle can be drawn from this change. Thus, it is not only possible to determine whether the contact piece is new or completely worn, but also to what extent the contact piece has been used.
The processing unit or the evaluation unit can carry out a pattern analysis of the measured values and/or parameters stored over a time period and derive a key figure from the pattern analysis. It can also be intended that the pattern analysis is carried out using artificial intelligence. The processing unit or the evaluation unit can correlate the measured values of different sensors and/or parameters and derive functional dependencies of the measured values and/or parameters. Thus, functional dependencies among the sensors can be examined. For example, vibrations or oscillations can be compared to a temperature and thus, it can possibly be determined that a bearing of the axle is damaged. In this manner, a number of other operating conditions and incidents can be detected and interpreted as a result of functional dependencies, for example loading statuses of the rail vehicle or the respective wagon, inclines and bends of the guide rail, the wear of the contact piece as a result of mechanical friction on the axle or its components, route sections of a guide rail with particularly turbulent operating characteristics of the axle and thus with particularly high or particularly low wear, a wear rate depending on the driving behavior, such as an acceleration or standstill of the rail vehicle, damage to components of the wheel set, the axle, the wheels, damage to wheel bearings and to the contact device, a discharge of current via the ground contact and thus resulting faults on components, the condition of wear components of the wheel set, such as bearings, joints and structural elements, loss of components, for example as a result of a collision with an obstacle, and a position, speed, acceleration and moving direction of the rail vehicle. These exemplary conditions and incidents can be addressed accordingly by maintenance measures, by adjusting the driving behavior of the rail vehicle or by implementing other suitable measures.
It can also be intended that the processing unit or the evaluation unit correlates signals or measured values of sensors and/or parameters which are not associated with the ground contact and signals or measured values of sensors and/or parameters which are associated with the ground contact. For example, by additionally taking into account signals or measured values and/or parameters of sensors of a current collector for a conductor rail, a pantograph, a wheel flange lubrication, a shaft grounding, etc.
A location of the ground contact can be determined by means of a position sensor of the sensing device, the location being associated to the parameters, the evaluation unit being configured to determine a state of wear of the guide rail. The position sensor can determined a position of the ground contact and thus a position of the vehicle via satellite navigation, for example. Thus, it can be determined, inter alia, at which point of a route a certain measured value of another sensor of the sensing device has been registered. Thus, the corresponding location can be associated with an incident or a measured value. Furthermore, it is possible to determine the state of wear of the guide rail by means of the evaluation unit, for example via an evaluation of the vibrations of the contact device or the contact piece caused by the wheels along the guide rail. Thus, the vibration pattern of the contact device can change when the guide rail is heavily worn. Furthermore, recesses, irregularities and arches along the guide rail can be determined and associated with a position on the route. This can have an influence on the speed of the rail vehicle in the sections of the route which have been localized in this manner.
The evaluation unit can process parameters of measuring units of a plurality of ground contacts. Thus, the evaluation unit can process parameters of a plurality of ground contacts which are disposed on individual rail vehicles or on a wheel set. The accuracy of a measurement or a monitoring can be increased further by comparing the parameters of the ground contacts. Furthermore, parameters of ground contacts which are disposed on different rail vehicles can be processed by means of the evaluation unit. This can also significantly improve the accuracy of measuring and monitoring the rail vehicles or the respective guide rails. Among other things, this provides a current and constantly changing status report on a route network and the vehicles operating in it. An optimization of the operating state resulting from this can significantly decrease operating costs. Monitoring the infrastructure and the rail vehicles regularly and frequently is also no longer necessary to this full extent and the operational safety is increased significantly. Furthermore, special measurement drives are no longer necessary.
The ground contact according to the invention for an axle of a wheel set of a rail vehicle has a housing unit, a contact device and a sensing device, the contact device having a contact piece which is disposed on a contact surface of the axle, an electrical sliding contact being formable between the contact surface and the contact piece, the ground contact comprising a measuring unit having a measuring device, at least one sensor of a sensing device of the measuring device being disposed on the contact device and/or adjacent to the contact device, a measured value of the contact device being registerable by means of the sensing device, the measured value being processable by means of a processing unit of the measuring device and a parameter describing an operating state of the wheel set and/or a guide rail being determinable. For further details on the advantages of the ground contact according to the invention, reference is made to the description of advantages of the method according to the invention. The housing unit can be formed by a housing body and a housing cover. Further advantageous embodiments of a ground contact are apparent from the description of features of the dependent claims referring back to method claim 1.
The monitoring system according to the invention comprises at least one rail vehicle having at least one ground contact according to the invention.
The monitoring system can comprise a plurality of measuring units and an evaluation unit for processing measured values and/or parameters of the measuring units of a plurality of ground contacts. As described above, it thus becomes possible to monitor a plurality of ground contacts of a rail vehicle or a plurality of rail vehicles having ground contacts using only one evaluation unit.
Thus, the monitoring system can comprise a plurality of rail vehicles, each having at least one ground contact. It can also be intended that the rail vehicles each have a plurality of ground contacts.
Further advantageous embodiments of a monitoring system are apparent from the description of features of the dependent claims referring back to method claim 1.
Hereinafter, the invention will be described in more detail with reference to the accompanying drawings.
A sensing device 61, which has an acceleration sensor (not further illustrated) is disposed within housing cover 24. The acceleration sensor or another suitable sensor can be disposed on housing unit 22 or contact device 26 or ground contact 20. The signals detected for the acceleration sensor are processed using a processing unit 62 of a measuring device 63 within housing cover 24 and are transmitted to an external network (not illustrated) via a transmitting unit 64. Furthermore, sensing device 61 comprises a temperature sensor 65 which is disposed on housing body 23 in this case.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/056097 | 3/10/2021 | WO |
