DE102004061870B3 - Sensor wheel for the acoustic examination of a test object and use of the sensor wheel - Google Patents

Abstract

Sensor wheel (S) for the acoustic examination of a test object with an ultrasound-permeable and sufficiently solid-shaped hollow roller (20) provided with two rim rings (22), which has a running surface (21) which can be placed on the test object. The sensor wheel (S) is provided with two wheel disks (90) and a wheel axle (40) which has a cylindrical container (41) which extends radially outward within the sensor wheel (S) and has a cylindrical surface (42) which is ultrasound-permeable at least in a partial region , Furthermore, the sensor wheel (S) has an ultrasound-permeable liquid coupling means between the roller (20) and the container (41), wherein the container (41) comprises at least one ultrasonic transducer (50) generating ultrasound radiation and the ultrasound radiation is transmitted through the coupling means, the roller (20). and the running surface (21) can be emitted into the test object. At least one such sensor wheel (S) is to be used for the examination of railway tracks and / or railway wheels.

Description

The invention relates to a sensor wheel for the acoustic examination of a measurement object with at least one ultrasound radiation generating transducer disposed within the sensor wheel and its use. A corresponding device for the acoustic examination of railroad tracks goes out of the US 4,174,636 or the EP 1 132 735 A1 out.

For the investigation of material properties of large-scale objects, such as railroad tracks, especially for diagnostics From defects, ultrasonic measurement methods have proven to be beneficial and reliable proved. For this purpose, ultrasound from a transducer in the too Sent object, reflected there and from the same or another sound transducer detected for further evaluation. For better coupling to the test object is because of the otherwise huge Reflection losses at the interface sound transducer air or Measurement object air between transducer and measured object usually a coupling agent, for example in the form of a liquid (eg water, oil), used. To constantly a liquid film between the transducer and the object to be measured, the converter must as parallel as possible over the to be examined object, otherwise the coupling film will tear off could. at large measuring objects is also to expect a high consumption of coupling agent, beyond that wetting on the surface being examined. Especially for the investigation Railroad tracks prove this ultrasonic measuring method for the reasons mentioned disadvantageous.

With the EP 1 132 735 A1 and US 4,174,636 are devices for fault detection on railroad tracks specified. Both writings are an ultrasonic measuring device in the form of a wheel that has to be rolled over it for inspection along a rail. In an inner region of the respective wheel, stationary ultrasonic transducers oriented in the direction of the measurement object are arranged, which do not rotate with the wheel during the measurement. The coupling of the ultrasonic transducer to the rail to be examined is carried out according to EP 1 132 735 A1 via a parallel to the rail slide plate, which slides away during the measurement on the inside of the corresponding wheel tire. Since the sliding plate presses the wheel just on the rail, a lubricant, in particular a liquid is used to reduce friction between the sliding plate and Radreifeninnen inside. The ultrasonic measuring device according to US 1,174,636 does not include sliding plates for coupling the ultrasonic signal. Here are the aligned in the direction of rail fixed sound transducer completely surrounded by coupling fluid, which fills the entire sealed cavity of the wheel. According to both mentioned writings the respective wheel interior is filled with liquid. Due to bubble formation and resulting vortex in the liquid both disclosed devices can only be operated at relatively low rotational speed of the wheel, which allow a maximum examination speed of about 50 km / h.

In published patent application WO 94/22008 A1 is a wheel-shaped ultrasonic measuring device indicated for the acoustic examination of railway tracks. One wedge-shaped body is within the wheel-shaped, with a coupling fluid filled Measuring device attached to the axis rotatably. Above the Axis are outside at the wedge-shaped body attached three ultrasonic transducers, with two ultrasonic transducers are aligned such that ultrasonic beams in the direction of to be examined rail outside on the body are send out. By means of the third ultrasonic transducer Ultrasonic rays are transmitted through a hole in the body sent this towards the rail. A fourth ultrasonic transducer is on a ausgestal ended as an extension piece Support such below the axis at an angle to the rail arranged that an oblique incidence Ultrasonic radiation is possible in the rail body. An increased blistering and turbulence within the wheel-shaped measuring device high speeds can with the design of the coupling fluid surrounded parts are not avoided within the measuring device.

In the published patent application DE 195 44 217 A1 an ultrasound testing device is provided for testing in particular test specimens designed as railroad tracks. In the apparatus, test head elements designed as electromagnetic ultrasonic transducers are arranged on a running surface of a test wheel. When unrolling the tread on a running surface of the railroad track, the received echo signals can be evaluated in dependence on the position of the test wheel that can be determined via a position detection device with a control and evaluation circuit.

In the patent US 3,541,840 is an ultrasonic sensor wheel for material testing of materials, especially in the field of aviation specified. In the apparatus, numerous ultrasonic transducers are arranged on a running surface of the sensor wheel in such a way that they are automatically activated and deactivated when rolling on a measurement object as a function of the orientation to the measurement object. The sensor wheel is further made of two wheel discs and three concentric rings formed with the wheel axle, the outer one of the rings, the tread and the ultrasonic transducers.

task The present invention is a sensor wheel of the aforementioned Indicate type, opposite the prior art, a higher Examination speed allows and universal can be used.

These Task is according to the invention solved with the measures specified in claim 1.

• – einer mit zwei Felgenringen versehenen, ultraschalldurchlässigen und hinreichend massiv ausgebildeten Hohlwalze, die eine auf das Messobjekt aufsetzbare Lauffläche aufweist,
• – zwei Radscheiben,
• – einer Radachse, die ein innerhalb des Sensorrades konzentrisch mit der Radachse ausgestaltetes und radial nach außen ausgedehntes zylinderförmiges Behältnis mit zumindest in einem Teilbereich ultraschalldurchlässiger Zylinderfläche aufweist, und
• – einem ultraschalldurchlässigen flüssigen Koppelmittel zwischen Walze und Behältnis wobei,
• – das Behältnis mindestens einen Ultraschallstrahlung erzeugenden Schallwandler umfasst und
• – die Ultraschallstrahlung durch das Koppelmittel, die Walze und die Lauffläche hindurch in das Messobjekt aussendbar ist.

The sensor wheel according to the invention is a sensor wheel for the acoustic examination of a test object

• An ultrasound-permeable and sufficiently solid-shaped hollow roller provided with two rim rings and having a running surface which can be placed on the object to be measured,
• - two wheel discs,
• A wheel axle which has a cylindrical container which is configured concentrically with the wheel axle within the sensor wheel and extends radially outwards, with cylindrical surface permeable to at least part of the wheel, and
• An ultrasound-permeable liquid coupling agent between the roller and the container,
• - The container comprises at least one ultrasound radiation generating sound transducer and
• - The ultrasonic radiation through the coupling means, the roller and the tread is passed through into the measurement object.

The associated with this embodiment of the sensor wheel advantages In particular, it can be seen that the entire area comprising the coupling agent within the sensor wheel as possible flow-friendly is designed so that at high relative speeds between little streaking of rotating and stationary parts of the sensor wheel, Turbulence and blistering occur in the coupling agent, the to density inhomogeneities in Lead coupling agent can. By the density inhomogeneities can depending on the expression the resolution deteriorates and overall the entire measurement signal can be falsified. One possible streamlined Configuration of the coupling means comprehensive area thus allows a faster rotational movement of the wheel and a concomitant higher Speed during the examination of the test object. This is Examination speeds of up to approx. 150 km / h are possible. Since that Sensor wheel according to the invention almost every surface shape can follow, without the measurement being distorted or even impossible, It can not only be used to examine linear objects, such as Railway rails, used, but also of curved objects. The sensor wheel is accordingly also for Examination of rollers or wheels, especially railway wheels, suitable.

advantageous Embodiments of the sensor wheel according to the invention will become apparent from the dependent of claim 1 Claims.

So the roller is at least partially made of a polymer plastic, in particular EPDM (ethylene-propylene-diene monomer) rubber. EPDM is a Polymer of ethylene, propylene and a low diene content. It is an elastic, good Ultraschallleitfähigkeit exhibiting material that to a great extent can withstand mechanical and thermal stresses. The Sensor wheel can thus be guaranteed good ultrasonic coupling Adjusting unevenness well on the measuring object surface is beyond that insensitive to mechanical and thermal stresses that occur at high examination speeds may occur.

Advantageous the sensor wheel has several over the cylindrical surface of the container distributed sound transducer on. This allows for a different Operating modes of the sensor wheel, such as "pitch-catch" mode and "pulse-echo" mode, on the other Can the sensor wheel with different, different requirements sufficient Ultrasonic transducers are provided, which are in position as needed to be brought. For this purpose, the sensor wheel axis adjustable with respect to a Wheel suspension can be performed.

It It is particularly advantageous that at least one first sound transducer for emitting ultrasonic radiation into the measurement object and at least one second sound transducer for receiving reflected ultrasonic radiation are designed from the measurement object. The sensor wheel can be operated in the so-called "pitch-catch" mode become. This has the advantage that in this mode the surface echo attenuated and thus a better detection of near-surface defects is achieved. In this version the sensor wheel can also special transducers are used, the only for sending or are designed only for receiving.

Advantageously, at least one sound transducer both for emitting ultrasonic radiation into the measurement object as well as for receiving reflected ultrasonic radiation from the Be designed measuring object. The sensor wheel can be operated in the so-called "pulse-echo" mode so that the ultrasound radiation can be radiated both vertically and at a different angle of incidence from the 90 ° into the test object, where it is reflected and returned to the sound transducer it is possible to simultaneously operate the sensor wheel according to the invention with several such combined transducers both in the "pulse echo" mode and in the "pitchcatch" mode.

It is cheap, at least one wheel disc has at least one valve for filling the Having coupling agent. The filling valve is thus easily accessible and guaranteed one possible easy filling.

For this It is advantageous that at least one wheel disc at least one another valve for venting of the sensor wheel during filling having the coupling agent. This can be achieved that the liquid Coupling agent without air residues in the the coupling means grasping area of the sensor wheel are filled can.

When Advantage proves that at least one wheel disc cooling fins having. In operation of the sensor wheel, especially at high speeds, warms up the entire sensor wheel on. With the cooling fins, the temperature can the coupling agent (eg degassed water, non-degassed water, oil) as possible be held constant to a change in the speed of sound in the liquid Coupling agent to avoid.

Further is cheap, that the sensor wheel at least one temperature sensor, in particular for coupling agent temperature determination. With knowledge of Coupling agent temperature can thus taking into account the temperature dependence the sound velocity a signal correction can be made.

Preferably the sensor wheel has at least one pressure sensor, in particular for coupling agent pressure determination. So it is possible, for example, a incoming coupling agent loss due to the associated To detect pressure drop.

Advantageous the sensor wheel has at least one position determining means on. Thus, the measured object can be measured in a spatially resolved manner. This is possible for example, with an integrated in the sensor wheel rotation angle, that is the position of the rotating hollow cylinder relative to the stationary sensor wheel axis determined, realized. But it can also with at least one of the wheel discs Be provided markings that can be evaluated, for example, via photoelectric sensors are. Such a means for determining position can also do so serve, the sensor wheel according to the invention with other examinations (eg track bed measurement) or measuring systems (eg eddy current measuring systems) to synchronize.

It is particularly advantageous that control means for driving the at least one sound transducer and / or means for signal processing are provided. It is convenient for this in that the control means and / or the signal processing means have at least a guided through the axis ladder are connected to the at least one sound transducer. Hereby can be in a particularly simple way a connection between on the one hand control means for controlling the at least one sound transducer and / or means for signal processing and on the other hand the at least one sound transducer create. For example, verzich tet on sliding contacts be in measuring operation, the sensor wheel with the at least a sound transducer does not rotate.

Besides is also an integration of the control means and / or the means for Signal processing favorable. This can be due to a wear-prone connection between one hand outside the sensor wheel arranged control means and / or the means for Signal processing and on the other hand with the rotating with the sensor wheel be dispensed with at least one sound transducer. Furthermore This achieves short distances between the at least one sound transducer on the one hand, and the control means and / or the signal processing means on the other hand. This reduces in particular the susceptibility to interference of analog signals. In particular, by a "vor Location "Digitization the measurement signals by means of the signal processing, leave For example, the digitized measurement signals are almost wireless trouble immune transferred to corresponding evaluation.

With The invention further provides a use of at least one sensor wheel according to the invention indicated for the examination of railway tracks and / or railway wheels. Due to the high examination speed of up to approx. 150 km / h are on the one hand particularly extensive measuring objects, such as railway tracks, and on the other fast rotating wheels, such as railway wheels in driving mode, because of the associated relative time savings to known Examination devices particularly suitable.

Preferred embodiments of the invention will now be explained in more detail with reference to the drawing. For clarity, the drawing is not drawn to scale, and certain features are shown only schematically. Show in detail

1 a sensor wheel according to the invention,

2 a sensor wheel according to the invention located on a test object in side view,

3 a sensor wheel according to the invention located on a test object in side view with integrated electronics,

4 a measuring arrangement for examining a railway wheel with two sensor wheels according to the invention and

5 schematically the control of a transducer and signal evaluation.

Corresponding parts are in the 1 to 5 provided with the same reference numerals.

In 1 an inventive sensor wheel S is shown in the sectional view. The sensor wheel S consists of one with two rim rings 22 provided, ultrasound-permeable and sufficiently massive trained hollow roller 20 , The hollow roller 20 has a tread 21 on that for a measurement on a surface 31 a measurement object 30 (please refer 2 to 4 ) is to be set up. The material of the hollow roller 20 should have good ultrasound properties for better acoustic coupling and moreover withstand high mechanical and thermal stresses. For this purpose, it is preferable to use an elastic material. For example, this is EPDM (ethylene-propylene-diene monomer), a polymer of ethylene, propylene and a low diene content in question. The two rim rings 22 in particular serve to stabilize the hollow roller 20 and for attachment of two wheel discs 90 , Preferably, the rim rings 22 from a metal. The connection between the rim rings 22 and the hollow roller 20 is preferably produced by vulcanization. Indicates the contact surface 93 between the respective rim ring 22 and the hollow roller 20 an advantageous contour, as in 1 indicated, the stability of the connection of the rim rings 22 with the hollow roller 20 be further increased. Moreover, the hollow roller can 20 also be provided with a support braid. Plastic rings for stiffening the hollow roller 20 are also possible.

The two wheel discs 90 are with fasteners 94 , such as screws, on the rim rings 22 attached. This results in a cavity 1 in the sensor wheel S, which is to be felt with an ultrasound-permeable coupling agent. The seal between wheel discs 90 and rim rings 22 takes place at suitable locations advantageously with O-rings. For more effective cooling, the wheel discs 90 on the outside of the sensor wheel S cooling fins 97 on. At least one of the two wheel discs 90 is with a filling valve 95 provided for the coupling agent. In addition, one of the two wheel discs with a vent valve 96 executed, thereby filling the cavity 1 controlled with the coupling agent, the displaced air and can escape completely. The two wheel discs 90 are opposite to the non-rotating wheel axle 40 each with a ball bearing 91 rotatably mounted. The sealing takes place in each case with the help of a Simmerrings 92 ,

The wheel axle 40 has a cylindrical inside the sensor wheel S radially outwardly extended cylindrical container 41 on, the container 41 is opposite to the filled with the coupling agent cavity 1 sealed for example with O-rings as well. The container 41 itself is z. B. filled with air. In the container 41 are one or more ultrasonic transducers 50 arranged. The cylindrical surfaces 42 of the container 41 In this case, the recesses positively surround the radiating surfaces 43 the sound transducer 50 , so that overall a smooth cylindrical surface 42 together with the radiating surfaces 43 the sound transducer 50 is guaranteed against the coupling agent. To avoid or minimize streaks and turbulence is thus a streamlined outer contour of the container 41 given. The cylindrical surface 42 of the container 41 can also be provided with a form-fitting with ultrasound-permeable windows, so that behind the windows also arranged tilted ultrasonic transducers 50 can be positioned (in 1 not shown). In addition, the wheel axle points 40 a hole 44 up, through the ladder 6 , For example, the control and signal lines of the sensor located in the sensor S ultrasonic transducer 50 , can be led to the outside.

In 2 is a on a test object 30 located inventive sensor wheel S shown in side view. In the container 41 are several sound transducers 50 evenly over the cylinder surface 42 of the container 41 distributed. From every transducer 50 leads a ladder 6 for drilling 44 in the wheel axle 40 and from there to the outside (in 2 not shown).

As an example of a measuring method is in 2 schematically shows the "pulse-echo" measurement method 50 Ultrasound both can send and receive. ultrasonic radiation 10 becomes perpendicular or at a small angle from the sound transducer 50 in the direction of the measuring object 30 sent out and reflected by this. Part of the reflected ultrasound radiation 11 then returns to the same transducer 50 , In the sound converter 50 becomes the received ultrasound 11 converted into an electrical signal and means 71 for signal processing via the conductor 6 transmitted. Should the entire measurement object 30 be examined, the inventive sensor wheel S with its tread 21 on the surface 31 of the measured object 30 walk along while the sound transducer 50 its relative orientation to the measured object 30 does not change. Will be one of the three remaining sound transducers 50 used, this must first be positioned. This can in particular the wheel axle 40 be made rotatable and detectable with proper positioning of the corresponding transducer. The advantage lies in the fact that the sensor wheel S, depending on the requirement, different sound transducers 50 be available. The sound transducer 50 may differ in that they operate at different ultrasonic frequencies and / or different bandwidths, that they are focused or unfocused ultrasonic radiation 10 send out or that they have ultrasound radiation 10 at different angles into the test object 30 radiate. As an example, in 1 continue a pressure sensor 60 and a temperature sensor 61 indicated, with which the pressure or the temperature of the coupling agent can be determined.

In 3 is a on a test object 30 located inventive sensor wheel S shown in side view with integrated electronics. In particular, this involves the integration of tax revenues 70 for controlling the sound transducer 50 and the integration of signal processing means 71 for conditioning (eg level adjustment, digitizing) of the converters 50 originating signals. This has the advantage that the signal paths are kept as short as possible, so that in particular the analog signals, for example, from the transducers 50 come, are afflicted with little disturbance. Advantageously, the control means 70 and signal processing means 71 Components of an integrated circuit that can be designed in a compact design. Next is in 2 a means for determining position 74 shown schematically, which may also be integrative part of the sensor wheel S according to the invention.

As an example of another method of measurement is in 3 The "pitch-catch" measurement method is shown 50 ultrasonic radiation 10 in the direction of the measuring object 30 which is reflected there. Part of the reflected ultrasound 11 then enters a second transducer 50 who serves as a recipient. There is the received ultrasound 11 converted into an electrical signal and the signal processing means 71 over the ladder 6 transmitted.

These two described measurement methods are not limited to the respective embodiments shown in FIG 2 and 3 established. They were only assigned to a figure for reasons of clarity. Both measuring methods can be distinguished both with the embodiment 2 as well as with the 3 be performed. A combination of both methods is conceivable.

4 shows an example of a use of the sensor wheel according to the invention S. Schematically represented are two sensor wheels S and a defect 80 having railway wheel 33 , As defects were here three around the axis 32 of the railway wheel distributed cracks 80 indicated. Upon rotation of the railway wheel 33 - indicated by arrows - all cracks happen 80 in the railway wheel 33 Ultrasonic radiation radiated from the first sensor wheel S. 10 and reflect them in a characteristic manner in the direction of the second sensor wheel S. In the second sensor wheel S, the reflected ultrasonic radiation 11 of at least one sound transducer 50 detected and to signal processing means 71 passed. The measuring method shown in this example is the "pitch-catch" measuring method described above, with the difference that here the first sensor wheel S only for transmitting and the second sensor S only for receiving ultrasonic radiation 10 . 11 are provided. Compared to the "pitch-catch" arrangement 3 With this arrangement, a significantly larger reflection angle range is available. The "pitchcatch" arrangement according to 4 Due to the extended reflection angle range, it can also be used advantageously to examine a measurement object that is nearly linearly extended (FIG. 30 ), such as railroad tracks.

To ensure the required pressure force from the sensor wheel S on the measurement object 30 . 33 can be integrated in the suspension of the sensor wheel S, a pressure sensor which monitors the pressure force. But the pressure force can also from the duration of the ultrasonic signal 10 . 11 from the transducer S to the measurement object or railway wheel surface 31 . 34 be determined. For this, however, a time change due to temperature change has to be considered.

Around Use sensor wheel S even at extremely low temperatures down to approx. -40 ° C to be able to can be added to the coupling agent antifreeze. Particularly advantageous proves for this purpose also in the Sensor wheel S integrated heating, which makes the coupling means more economical, constant temperature.

In 5 is shown as an example of a scheme for controlling a transducer S and signal evaluation. It becomes a container 41 arranged sound transducer 50 shown here as combined transmitter and receiver is executed. About a leader 6 is this sound transducer 50 with a switch 72 connected to the sound transducer 50 switches to a transmitter or receiver mode. The desk 72 , which may alternatively be replaced by a transmitting / receiving switch, is via the control means 70 controlled. The control means 70 includes a transmit pulse and a transmit amplifier. Is the arrangement as in 3 shown as an example, switched in a transmission mode, is via the transmitting pulse, which is connected to the transmission amplifier, the sound transducer 50 supplied with amplified transmission pulses. If the arrangement is switched in a receive mode, those in the sound transducer 50 generated electrical signals to the agent 71 transmitted for signal processing. The signal processing means 71 includes, for example, a receiver amplifier with time-controlled amplification factor (TGC: "Time Gain Correction") and an analog filter 50 amplified, normalized and filtered. With the filter while a noise reduction is achieved. The signal processed in this way then passes for digitizing into an analog / digital converter which is likewise contained in the signal processing means, for example. The thus generated digital signals can be in an evaluation 73 be further processed with a digital signal processor by further reducing the digitized received data with digital filters. A software associated with the digital signal processor evaluates the received signals, in particular with the aim of defects 80 in the test object 30 to register and determine. To reduce the data rate, this data is again reduced by means of digital compression. By means of a transformer, for example, the evaluation results can then be sent to a receiving unit located remotely, for example by means of an electrical connection or also contactless by means of infrared or radio.

Claims (15)

Sensor wheel for the acoustic examination of a test object ( 30 ) with - one with two rim rings ( 22 ) provided, ultrasound-permeable and sufficiently massive trained hollow roller ( 20 ), one on the measuring object ( 30 ) mountable tread ( 21 ), - two wheel discs ( 90 ), - a wheel axle ( 40 ), one within the sensor wheel (S) concentric with the wheel axle ( 40 ) and radially outwardly extended cylindrical container ( 41 ) with at least a partial region of ultrasound-permeable cylindrical surface ( 42 ), and - an ultrasound-permeable liquid coupling agent between roller ( 20 ) and container ( 41 ), where - the container ( 41 ) at least one ultrasonic radiation ( 10 ) generating sound transducer ( 50 ) and - the ultrasonic radiation ( 10 ) by the coupling agent, the roller ( 20 ) and the tread ( 21 ) into the test object ( 30 ) is send out. Sensor wheel (S) according to claim 1, characterized in that the roller ( 20 ) consists at least partially of a polymer plastic, in particular EPDM rubber. Sensor wheel (S) according to claim 1 or 2, characterized by several over the cylindrical surface ( 42 ) of the container ( 41 ) distributed sound transducer ( 50 ). Sensor wheel ( 5 ) according to one of the preceding claims, characterized in that at least one first sound transducer ( 50 ) for emitting ultrasound radiation ( 10 ) into the measuring object ( 30 ) and at least one second sound transducer ( 50 ) for receiving reflected ultrasound radiation ( 11 ) from the measurement object ( 30 ) are designed. Sensor wheel (S) according to one of claims 1 to 3, characterized by at least one sound transducer ( 50 ) both for emitting ultrasonic radiation ( 10 ) into the measuring object ( 30 ) as well as for receiving reflected ultrasonic radiation ( 11 ) from the measurement object ( 30 ). Sensor wheel (S) according to one of the preceding claims, characterized in that at least one wheel disc ( 90 ) at least one valve ( 95 ) for filling the coupling agent. Sensor wheel (S) according to claim 6, characterized in that at least one wheel disc ( 90 ) at least one valve ( 96 ) for venting the sensor wheel (S) when filled with the coupling means. Sensor wheel (S) according to one of the preceding claims, characterized in that at least one wheel disc ( 90 ) Cooling fins ( 97 ) having. Sensor wheel (S) according to one of the preceding claims, characterized by at least one temperature sensor ( 61 ), in particular for coupling agent temperature determination. Sensor wheel (S) according to one of the preceding claims, characterized by at least one pressure sensor ( 60 ), in particular for coupling medium pressure determination. Sensor wheel (S) according to one of the preceding claims, characterized by at least one means ( 74 ) for position determination. Sensor wheel (S) according to one of the preceding claims, characterized by control means ( 70 ) for controlling the at least one sound transducer ( 50 ) and / or signal processing means ( 71 ). Sensor wheel (S) according to claim 12, characterized in that the control means ( 70 ) and / or the agent ( 71 ) for signal processing via at least one axis ( 40 ) guided ladder ( 6 ) with the at least one sound transducer ( 50 ) are connected. Sensor wheel (S) according to claim 12, characterized by an integration of the control means ( 70 ) and / or the signal processing means ( 71 ). Use of at least one sensor wheel (S) according to one of the preceding claims for the examination of railway rails and / or railway wheels ( 33 ).