OFFSET DETECTION BETWEEN JOINED COMPONENTS

Abstract

The invention relates to a device, to a system, and to a method for detecting an offset between two joined, in particular pressure joined components during operation of said components and to the use of an RFID transponder for detecting an offset between two joined, in particular pressure joined components during operation of said components. In respect of the device, there is a first element, provided for attaching to one of the components, and a second element, provided for attaching to the other of the components, wherein the first and second element are coupled and/or can be coupled to each other across a joint of the components such that an offset influences the coupling, wherein the device furthermore has a transmission unit, which is designed to transmit a state and/or a dimension of the coupling without contact.

Claims

1. A device for detecting an offset between two joined, in particular pressure joined components during operation of said components, comprising: a first element, which is provided for attaching to one of the components, and a second element, which is provided for attaching to the other of the components, wherein the first and the second element are coupled and/or can be coupled to each other via a joining point of the components such that an offset influences the coupling, wherein the device furthermore has a transmission unit, which is designed to transmit a state and/or a dimension of the coupling without contact.

2. The device according to claim 1, wherein the transmission unit has a passive RFID transponder for contactless transmission.

3. The device according to claim 1, wherein the coupling between the first and the second element has an electrical line, which is designed to be interrupted by an offset which exceeds a predetermined amount, and/or wherein the coupling has electrically conductive parts which can be brought into contact with each other by an offset which exceeds a predetermined amount.

4. The device according to claim 3, wherein the electrical line has a conductive metal plate with two attachment regions for respective attachment to one of the components, and a constriction located between the attachment regions, wherein the constriction is designed to break in the event of an offset which exceeds a predetermined amount.

5. The device according to claim 3, wherein the coupling comprises a plurality of electrical lines which are each designed to be interrupted in the event of an offset which exceeds a different associated amount.

6. The device according to claim 2, wherein the coupling has three or more electrically conductive parts, of which at least two can be brought into contact with each other by an offset which exceeds a predetermined amount.

7. The device according to claim 1, wherein the coupling between the first and the second element comprises a coupling via an electrical, magnetic and/or electromagnetic field.

8. The device according to claim 7, wherein the first element has a Reed switch and the second element has a magnet and/or a magnetic coil.

9. The device according to claim 7, wherein the first element and the second element each have one coil from a pair of coils, and/or the first element and the second element each have an electrode of a capacitor, and/or the first element and the second element have an antenna and a parasitic antenna element.

10. The device according to claim 1, wherein the coupling between the first and the second element comprises a strain gauge which is designed in particular for arrangement along and/or transverse to the offset direction.

11. A system for monitoring an offset between two joined, in particular pressure-joined components during operation of said components, comprising: at least one device for detecting an offset, according to claim 1, a receiver unit, which is adapted to receive a state of the coupling transmitted contactlessly by the transmission unit of a device and/or to receive a dimension of the coupling transmitted contactlessly by the transmission unit of a device and to output a corresponding signal, and an evaluation unit, which is adapted to evaluate the offset between the components on the basis of a signal outputted by the receiver unit.

12. A method for detecting an offset between two joined, in particular to pressure-joined components during operation of said components, comprising the steps of: attaching a first element to one of the components, attaching a second element to the other of the components, wherein the first and the second element are attached in such a way that the first and the second element are coupled and/or can be coupled to each other via a joining point of the components such that an offset influences the coupling, detecting a state and/or a dimension of the coupling and contactlessly transmitting the detected state and/or dimension of the coupling.

13. A method for detecting an offset between two joined, in particular pressure-joined components during operation of said components, wherein an RFID transponder is attached over a joining point of the components, such that an offset between the components that exceeds a predetermined amount destroys the RFID transponder and/or modifies it in a predetermined manner such that a dimension of the offset can be seen from a signal response of the RFID transponder.

14. The device according to claim 2, wherein the coupling between the first and the second element has an electrical line, which is designed to be interrupted by an offset which exceeds a predetermined amount, and/or wherein the coupling has electrically conductive parts which can be brought into contact with each other by an offset which exceeds a predetermined amount.

15. The device according to claim 14, wherein the electrical line has a conductive metal plate with two attachment regions for respective attachment to one of the components, and a constriction located between the attachment regions, wherein the constriction is designed to break in the event of an offset which exceeds a predetermined amount.

16. The device according to claim 14, wherein the coupling comprises a plurality of electrical lines which are each designed to be interrupted in the event of an offset which exceeds a different associated amount.

17. The device according to claim 3, wherein the coupling has three or more electrically conductive parts, of which at least two can be brought into contact with each other by an offset which exceeds a predetermined amount.

Description

[0051] The invention shall now be described with reference to the embodiments and to the enclosed Figures, in which

[0052] FIG. 1 shows a schematic view of a wheelset fitted with wheel tyres, in which the present invention can be deployed,

[0053] FIG. 2 shows a schematic view of a first embodiment of the device according to the invention,

[0054] FIG. 3 shows a schematic view of one aspect of a second embodiment of the device according to the invention,

[0055] FIG. 4 shows a schematic view of one aspect of a third embodiment of the device according to the invention,

[0056] FIG. 5 shows a schematic view of one aspect of a fourth embodiment of the device according to the invention,

[0057] FIG. 6 shows a schematic flow diagram of an embodiment of the use according to the invention,

[0058] FIG. 7 shows a schematic view of an embodiment of the system according to the invention,

[0059] FIG. 8 shows a flow diagram of an embodiment of the method according to the invention,

[0060] FIG. 9 shows a schematic view of a conductive metal plate, as an example of an electrical line and showing one aspect of the second embodiment of the device according to the invention and

[0061] FIG. 10 shows a schematic cross-sectional view of the metal plate in FIG. 9, on two components.

[0062] FIG. 1 shows a schematic view of a wheelset fitted with wheel tyres, in which the present invention can be deployed.

[0063] A wheel disc 2 is pressed onto wheelset shaft 1. Wheelset shaft 1 is mounted via a rolling bearing 3 in a bearing housing 4. A wheel tyre 5 is pressed onto wheel disc 2. This means there are two press fits: a first press fit 6 between wheelset shaft 1 and wheel disc 2, and a second press fit 7 between wheel disc 2 and wheel tyre 5.

[0064] Said press fits 6, 7 can be checked and monitored during operation for an offset by means of a device according to the invention and with a corresponding method according to the invention.

[0065] FIG. 2 shows a schematic view of a first embodiment of the device according to the invention.

[0066] A device according to the invention 20 is arranged in such a way on two components 8, 9, which are joined by a press fit 10, for example, that a change in device 20 occurs when distortion or displacement occurs between the pair of components. Device 20 comprises an RFID transponder 21 which performs higher-level functions in additional to the known capability of storing data. Said transponder 21 is connected in a sensor arrangement to a first element 22, a second element 23 and to a coupling 24 between said elements 22, 23. The RFID transponder detects the current state of the sensor arrangement, and any change in that state, and passes the information wirelessly by radio to an RFID reader (not shown here, see FIG. 7).

[0067] Device 20, comprising transponder 21 and a sensor arrangement connected thereto, operates in passive mode, i.e. the transponder draws its energy from the radiation field of the RFID reader. Device 20 is therefore maintenance-free.

[0068] The state detected by the sensor is read out, for example, when passing by a plurality of defined measuring stations each equipped with an RFID reader.

[0069] In an advantageous practical implementation, the following technical features ensue for the device:

[0070] The transponder is a passive component of robust design so that it monitors the prevailing environmental conditions, in the form of temperature, shocks, centrifugal forces, humidity, water splashes, chemical solvents, effects of foreign matter and EMC effects, without functional limitations.

[0071] The sensor arrangement is arranged in such a way over the potential separation point that it changes or loses contact in the event of distortional movements or displacements. This can be interpreted as a measure of divergence.

[0072] The sensor arrangement, and its coupling 24, may be a break sensor, for example, which interrupts an electrically conductive connection in the event of any displacement or distortional movement. Another possible form involves the use of a Reed relay mounted on the one side of the press fit, and a magnetic counterpart on the opposite side of the press fit, which opens and closes its contact in response to the magnet being distorted.

[0073] The sensor arrangement is thus attached to both of the components to be monitored (e.g. by gluing, clamping, stapling, screwing, embedding, etc.), in such a way that any mechanical change (displacement or distortional movement) causes a change in the state of the sensor arrangement and concomitantly in the transponder signal.

[0074] When the transponder passes an RFID reader, a transponder identifier (ID) uniquely associated with the vehicle/wheelset or wheel is read out and stored, in addition to the sensor status.

[0075] Any changes or failures in the transponder identifier allow conclusions to be drawn abut changes in the mechanical integrity of the monitored components and trigger the respective control and repair measures in respect of the object in question.

[0076] For the sake of clarity and simplicity, only elements 22, 23 of the device, and the coupling via the point of separation 10 of components 8, 9, are shown in in FIGS. 3-5.

[0077] FIG. 3 shows a schematic view of one aspect of a second embodiment of the device according to the invention.

[0078] Elements 22, 23 are attached respectively to one of components 8, 9, elements 22, 23 being coupled to one another by an electrical line 25 in the form of a wire, for example, or a shaped metal plate (see FIGS. 9 and 10 below). If an offset between components 8, 9 occurs (i.e. a relative displacement between the components, to the left or right in the view shown in FIG. 3) wire 25 or metal plate 25 is destroyed.

[0079] FIG. 4 shows a schematic view of one aspect of a third embodiment of the device according to the invention.

[0080] In this aspect also, elements 22, 23 are mounted on components 8, 9, namely in such a way, in a state without any offset (as shown here), that a Reed switch 26 of element 22 is located opposite a magnet 27 of element 23.

[0081] When components 8, 9 move relative to each other along press fit 10, in other words when an offset ensues, magnet 27 is moved away from Reed switch 26, which is then opened so that the offset becomes discernible for the device.

[0082] FIG. 5 shows a schematic view of one aspect of a fourth embodiment of the device according to the invention.

[0083] Elements 22, 23 are connected to each other by a strain gauge 28 and are mounted on components 8, 9 in such a way that one element 22, 23 is securely joined (e.g. glued) in each case to one of components 8, 9. A respective part of elements 22, 23 extends into the region of the respective other component 8, 9, but it is not attached there. Strain gauge 28 is attached to elements 22, 23 only, but not to components 8, 9. In this aspect, additionally, there is another strain gauge 29 which is not involved directly in detecting the offset. Given that temperature variations and other influences can jointly act on strain gauges 28, 29, the offset, which merely acts on strain gauge 28, can be determined from the difference in signals from strain gauges 28, 29.

[0084] FIG. 6 shows a schematic view of an embodiment of the use according to the invention.

[0085] An RFID transponder 30 is securely joined by a press fit 10 (as an example of a joint) between two components 8, 9 to said two components 8, 9, for example by gluing.

[0086] Any offset exceeding a predetermined amount and arising between components 8, 9 will destroy RFID transponder 30. The respective offset can be concluded from the fact that a response to a request no longer occurs.

[0087] Alternatively, the offset can modify the RFID transponder in a predetermined manner such that a measure of the offset can be derived from a signal response of the RFID transponder. This may also be based on partial destruction of the RFID transponder, for example by selective ripping of a part of the RFID transponder without doing away with its overall function.

[0088] FIG. 7 shows a schematic view of an embodiment of the system according to the invention.

[0089] In practice, system 40 comprises a plurality of devices 20 according to the invention, a plurality of receiver units 31 which each receive a state of the coupling transmitted contactlessly by the transmission unit of device(s) 20 and/or which each receive a measure of the coupling transmitted contactlessly by the transmission unit of devices (20) and output a corresponding signal, and a plurality of evaluation units 32 which evaluate the offset between the components on the basis of a signal received from the receiver unit (only one of each shown here).

[0090] In one implementation in which the transmission unit is an RFID transponder, the receiver unit can be considered an RFID reader 31.

[0091] Data handling is based on the state at the transponder being read out by means of an antenna connected to reader 31. The reader/antenna unit can be installed on the vehicle and travel with it, or may be in the form of a fixed, stationary installation.

[0092] A local computer unit 32 which associates the states at the transponders, in combination with the specific transponder ID, with the individual vehicles, bogies, wheelsets and wheels, and transfers the resultant data to a respective database. When a plurality of readers 31 are used, local computer units 32 are connected in a network (not shown) and pass the fetched states directly to a central computer unit (not shown), on which they are then assigned accordingly and entered in a database.

[0093] Parallel to their detection, the respective states are analysed. Potential distortions and missing transponders are indicated, for example by a relay signal.

[0094] False alarms based on fully transmitted data packets are precluded due to binary detection of states. However, in order to prevent false reports due to incomplete or untransmitted data packets, several read-out cycles with an identical result (i.e. the detection of an offset) are preferably required before an alarm signal is given.

[0095] FIG. 8 shows a flow diagram of an embodiment of the method according to the invention.

[0096] The method for detecting an offset between two components firstly comprises a first attachment step 51 in which a first element is attached to one of the components and a second attachment step 52 in which a second element is attached to the other of the components. The first and the second elements are attached in such a way that the first and the second elements are coupled to each other via a joining point of the components in such a way that an offset affects the coupling. In the following detection step 53, a state and/or a measure of the coupling is detected, wherein the detected state and/or measure of the coupling is contactlessly transmitted in a transmission step 54. The transmission may also include a negative statement, for example in the form that transmission continues as long as the predetermined offset has not yet occurred, whereas occurrence of the predetermined offset results, for example due to destruction of the device, to no further transmission being carried out.

[0097] FIG. 9 shows a schematic view of a conductive metal plate as an example of an electrical line, as one aspect of the second embodiment of the device according to the invention.

[0098] As already noted above with reference to FIG. 3, the electrical line, breakage of which indicates an offset exceeding a predetermined amount, can also be realised by a suitably shaped metal plate.

[0099] Such a metal plate 25 is shown in FIG. 9. Metal plate 25 has two planar attachment regions 36, which are shown here with holes 33 for rivets or the like. Instead of, or in addition to such a mechanical connection, attachment regions 36 may also be glued to the components (see FIG. 10). In this case, holes 33 may serve as assembly aids or to ensure a non-conductive connection to the respective component.

[0100] Between attachment regions 36, metal plate 25 has a constriction 35 at which the cross-section of the metal plate is reduced to such an extent that an offset between attachment regions 36 (and thus between the components) results in breakage at the constriction and thus to the electrical line being interrupted.

[0101] In the case shown here, the direction of the offset is transverse to constriction 35 (see FIG. 10), although other orientations are also possible, however.

[0102] Metal plate 25 has two kinks 34, as also shown in FIG. 10. Metal plate 25 is not limited, therefore, to cases in which the components are arranged in alignment with each other. However, this example is not to be understood as a limitation, because other shapes of metal plate are also possible in order to adapt metal plate 25 to the geometry of the components. In particular, it is not necessarily the case that the parts of the metal plate are planar as such, because attachment regions 36, above all, can be adapted to the contours of the components (either by previous shaping or not until they are being attached).

[0103] FIG. 10 shows a schematic cross-sectional view of metal plate 25 from FIG. 9 on two components 8, 9. Components 8, 9 have a joining point 10, and metal plate 25 is attached to components 8, 9 with the aid of attachment regions 36 in such a way that intermediate region and in particular the construction (not shown in FIG. 10) extend over the joining point.

[0104] Fastening regions 36 abut components 8, 9 at least partially, and metal plate 25 has kinks 34 such that metal plate 25 as a whole basically follows the contour of combined components 8, 9.

[0105] In particular, kinks 34 (or other regions of metal plate 25) may be under mechanical tension when installed. If the tension in the two kinks 34 acts in the same direction, or also if it acts in opposite directions, the respective tension is removed in the event of the constriction breaking, in which case the breaking points move away from each other as a result of the tension being removed. For example, the individual parts between kinks 34 and separated from each other as a result of the break, could move in the clockwise or anti-clockwise direction (in FIG. 10), in order to produce additional so spatial separation in the event of the constriction breaking.